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Hepatitis B Virus. INTRODUCTION. High incidence rate Do not grow in the laboratory Discovered in 1964. The Hepatitis Viruses. Viral Hepatitis - Overview. PROPERTIES. Classification Hepadnaviridae Infect only human Morphology Icosahedral (Dane + Filaments & Sphere particles) Enveloped
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INTRODUCTION • High incidence rate • Do not grow in the laboratory • Discovered in 1964
PROPERTIES Classification • Hepadnaviridae • Infect only human Morphology • Icosahedral (Dane + Filaments & Sphere particles) • Enveloped *Dane particle:DNA + Polymerase + HBcAg + HBeAg) Filaments + Spheres particles:HBsAg
ANTIGENS & ANTIBODIES HBsAg HBeAg Anti-HBcAnti-HBeAnti-HBs Symptoms, InfectionLittle infection / Complete recovery Start of recovery (Convalescence)
Postnatal infection: • Acute hepatitis:Rash Jaundice - 90% recovery - 10 % chronic or death • Chronic antigenaemia: - Dealy Anti-HBe - No Anti-HBs
Chronic aggressive (Active) hepatitis:- No Anti-HBe - No Anti-HBs • Hepatocellular carcinoma: Integration of viral genome in the DNA of hepatocytes Death
Perinatal infections • Infected mother Baby: - Uterus - During delivery - Close contact * Cirrhosis or liver cancer Death
EPIDEMIOLOGY Mode of transmission: • Blood • Body fluid (Cervical secretion, semen, milk) • High – risk group
Concentration of Hepatitis B Virus in Various Body Fluids Low/Not High Moderate Detectable blood semen urine serum vaginal fluid feces wound exudates saliva sweat tears Breast milk
Acute Viral Hepatitis Died of Hepatoma
IMMUNE RESPONSE • Anti-HBs :(Complete recovery) • Cytotoxic T cells: (Much of liver damage is due to it)
Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course Symptoms anti-HBe HBeAg Total anti-HBc Titer anti-HBs IgM anti-HBc HBsAg 0 4 8 12 16 24 28 32 52 100 20 36 Weeks after Exposure
Progression to Chronic Hepatitis B Virus Infection Typical Serologic Course Acute (6 months) Chronic (Years) HBeAg anti-HBe HBsAg Total anti-HBc Titer IgM anti-HBc Years 0 4 8 16 20 24 28 36 12 32 52 Weeks after Exposure
LABORATORY DIAGNOSIS • Non-specific tests:Test for liver enzymes • Specific tests: - Serology: . ELISA: HBsAg, HBeAg, Anti-HBc, Anti-HBeAg, Anti-HBsAg
HBsAg -ve +ve No disease Confirmation test -ve +ve Profile tests: . Anti-HBc (IgG,IgM.Total) . HBeAg . Anti-HBe . Anti-HBs
. Reverse passive hemagglutination . Latex test • EM • DNA polymerase
Control • Specific treatment: - IFN-Alpha for 6 months (For HBeAg +ve, acute case, no need for treatment) * Do not work in infancy infection - DNA polymerase inhibitors Immunization • Recombinant vaccine (HBsAg) • IgG
Current Treatment Options for HBV • Interferon alpha 2b (Intron A): General • Lamivudine (Epivir HBV): RT inhibitor • Hepsera (Adefovir dipivoxil): RT inhibitor